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Fix Double NAT (Strict NAT Type) Issues

Two routers are performing Network Address Translation in series, leading to strict NAT types in gaming and broken port forwarding.

double-natstrict-natgamingrouter-config

Confirmed working on: Routers · Xbox · PlayStation · PC

Before you begin

Match the environmentUse this guide only for Routers, Xbox, PlayStation, PC or a clearly compatible setup.
Protect recoveryBack up important data and save encryption or account recovery keys before changing system state.
Know when to stopThis guide includes advanced changes. If the device contains irreplaceable data or belongs to an employer, stop and use a qualified technician.

Problem overview

You are experiencing a “Strict NAT” or “NAT Type 3” error on your gaming console, or port forwarding rules are completely failing. This happens when traffic passes through two separate routers that both perform Network Address Translation (Double NAT).

Common causes

  • Connecting a personal Wi-Fi router to an ISP-provided gateway that is also acting as a router
  • Using a mesh network system behind an existing router
  • Your ISP uses Carrier-Grade NAT (CGNAT) on their end

Solution 1: Enable Bridge Mode on the ISP router

  1. Identify the IP address of your ISP-provided gateway (usually 192.168.1.254 or similar) and log into its web interface.
  2. Navigate to the Advanced, WAN, or Routing settings.
  3. Look for an option called Bridge Mode, IP Passthrough, or Modem Only Mode.
  4. Enable this mode. The ISP device will now act solely as a modem, passing the public IP directly to your personal router.
  5. Save and restart both the modem and your personal router.
Expert Tip

If your ISP uses PPPoE authentication, you may need to enter your ISP username and password into your personal router’s WAN settings after enabling Bridge Mode.

Solution 2: Put your personal router in AP Mode

  1. If you cannot change settings on the ISP router, you can disable the routing functions on your personal router.
  2. Log into your personal router’s interface.
  3. Find the Operation Mode or Advanced Settings.
  4. Switch the mode from Router to Access Point (AP) Mode.
  5. Save the settings. Your personal router will now only broadcast Wi-Fi, leaving the ISP router to handle all NAT and DHCP duties.

Solution 3: Use the DMZ setting (Workaround)

  1. Log into your ISP-provided gateway.
  2. Find the IP address assigned to your personal router (e.g., 192.168.1.50).
  3. Navigate to the Security or Firewall section and find DMZ.
  4. Enable DMZ and point it to the personal router’s IP address.
  5. This forwards all inbound traffic straight to your personal router, bypassing the ISP router’s NAT firewall.

Solution 4: Verify you are not behind CGNAT

  1. Log into your personal router (if AP mode) or modem (if bridge mode).
  2. Check the WAN IP Address listed in the status page.
  3. Go to whatismyip.com on your browser and compare the IP address.
  4. If they do not match, your ISP is using CGNAT.
  5. You must call your ISP and ask to opt-out of CGNAT or purchase a static IP address to fix the Double NAT.
Caution

Do not put your PC or gaming console directly into the DMZ of your primary edge router unless absolutely necessary for troubleshooting, as it removes all hardware firewall protections.

Confirm the result

  1. Repeat the exact action that originally triggered the problem.
  2. Confirm the original error or symptom is gone and no new warning has appeared.
  3. If the guide changed a driver, service, package, or system setting, restart once and test again.
  4. If the result is worse or unexpected, stop. Reverse only the last change using its documented restore option; if none is documented, use your backup or qualified support.

Questions about this fix

How do I check if I have a Double NAT?

Run a tracert command to an external IP. If the first two hops are private IP addresses (like 192.168.x.x and 10.0.x.x), you have a Double NAT.

Does Double NAT affect normal web browsing?

No, basic web browsing and video streaming work perfectly fine through a Double NAT. It only impacts peer-to-peer gaming and inbound hosting.

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